Patricio O’Ward produced a second dominant win of the Pro Mazda round on the Indianapolis road course.
The Mexican, who’s yet to secure a deal for the full season, pulled away from Pelfrey team-mate Aaron Telitz to win by 4.7 seconds.
Juncos driver Will Owen held third throughout, but finished 21 seconds behind O’Ward.
His team-mates Garett Grist, Nicolas Dapero and Jake Parsons battled over fourth place early on but it was USF2000 champion Nico Jamin who came through to claim the position from Grist on the very last lap.
Parsons held off Jake Eidson for sixth, with Dapero slipping back to eighth ahead of Bobby Eberle and Kevin Davis.